August 2013

Out on a limb: Might as well jump

One of the biggest challenges in sports injury prevention is that the sheer number of potential injuries makes it prohibitive to screen for all of them. But what if there was a single test that could be used to screen for all lower extremity injuries? It’s not as farfetched as you might think.

We’ve known for decades that the way athletes land from a jump can help predict their risk of anterior cruciate ligament (ACL) injury. More recently, researchers have also determined that landing mechanics can help predict risk of patellofemoral pain (PFP), despite the fact that acute ACL injuries and chronic PFP occur in different patient populations and through different mechanisms.

And now, one of the groups at the forefront of research on ACL injury and PFP has reported that landing mechanics can also be used to screen for a third category of injury risk that would seem to be even further removed from the first two. The multicenter, multiyear, military-focused JUMP-ACL (Joint Undertaking to Monitor and Prevent ACL Injury) project has led to a number of advances in the understanding of ACL injury, PFP, and their common risk factors. And now, as reported in this issue of LER, an analysis of a portion of the same database suggests that the mechanics of landing from a jump can predict risk of lower extremity stress fractures (see “Stress management: Landing mechanics predict fracture risk”).

Researchers from Cincinnati Children’s Hospital Medical Center in Ohio have determined that the clinic-friendly tuck jump test can be used to identify landing-related risk factors for ACL injury without the need for expensive, complicated laboratory testing equipment. Given that landing mechanics are also predictive of PFP and lower extremity stress fracture risk, it’s not inconceivable that the same test could be used to screen for all three conditions.

Those studies haven’t yet been done, and, even if one test does appear to be predictive for ACL injury, PFP, and stress fracture, that still doesn’t cover all lower extremity injuries. But the medical literature is filled with findings that suggest connections between landing mechanics and other injuries.

A 2001 cadaver study from the US Air Force Academy in Colorado Springs found that landing technique had a significant effect on Achilles tendon stiffness. And a 2000 mechanical modeling study from the University of Calgary found that increased plantar flexion on landing from a jump predicted an increased risk of ankle sprain. So it’s really not that much of a stretch to think that the tuck jump test—or some version of it—could also be used to predict risk of Achilles injury or ankle sprain. And those are just two examples that come to mind.
The possibilities are many.

Most of us imagine that the future of healthcare involves making advanced technology more accessible. But the future of lower extremity injury prevention might well revolve around a screening test that involves simply watching an athlete jump and land. And that future is well within our reach.